My BIL hates to split wood but has a 65HP Massey and a massive vertical
3ph splitter he built with a 4" ram. I borrowed it (he hadn't used it in years), leaned it up against my woodshed (tied the top) and hooked it to the power beyond of my JD 4300. Worked good but slow. I finally bought a 2.5" cylinder for it and things speeded up considerably.
I then spotted another home-made splitter sitting at a buddies.(His wife later told me that she's been cutting the grass around it for 7yrs as he has a self contained that he uses instead) This splitter has a longer 2.5" cylinder with a narrow fixed wedge and moveable push pad. The rest of the splitter is built around a ten foot long 5" square tube (1/2" wall) and weighs twice what it needs to. This one I left laying on blocks (horizontal) and find that it just keeps pushing the split pieces out of the way as I work. They get piled by my helpers.
In my case I haul or skid the logs to the woodshed where they are cut up and pushed into a pile beside the splitter. When I decide to split for a while, I just plug into the splitter, rev up to 1200rpm and turn up the FM....I seldom split anything over 14" diameter so lifting the blocks onto the splitter isn't a problem. I split about 5 bush cords this fall and still have another pile of dried hardwood logs sitting there as an emergency supply if its a cold winter.
A stand alone/self contained would only appeal to me if it were a tiltable unit with an electric start, on big wheels and really inexpensive..... ;-)